Many scientific and engineering applications require individuals to be able to see and manipulate items which are not visible with the naked eye. Semiconductor manufacturers, for example, must be able to examine and probe micro and nano-scale circuits fabricated on various substrates. Similarly, biological researchers must be able to see and manipulate cells, proteins, micro-organisms and other microscopic elements within their laboratories. Microscopic and metrologic applications are as prevalent and diverse as the engineers, scientists and developers (collectively, end-users) who promulgate them. However, existing tools do not provide many of the features desired by these end-users.
Optical microscopes allow end-users to see many objects too small to be visible to the unaided eye. Compound microscopes, in use since the late 1500 s, typically use a plurality of lenses to magnify an image. Modem compound microscopes use multiple glass lenses within the objective and ocular assemblies. In addition, modern compound microscopes typically provide multiple objective lenses, which may be rotated or otherwise interchanged, such that a single compound microscope can magnify an object up to about 1000×, in discrete steps (e.g., 4×, 10×, 400×, etc.).
Currently, optical zoom systems are used in microscopes in conjunction with an objective lens to provide a continuously variable magnification. Zoom systems are typically composed of two or more individual lenses whose axial position relative to one another is varied by some mechanical means. Often motors are used to facilitate the motion of the individual lenses.
The stereo, binocular or dissecting microscope is similar to the compound microscope, except that it uses two eyepieces (or sometimes two complete microscopes) to provide slightly different viewing angles to the left and right eyes. In this way, the stereo microscope produces a three dimensional visualization of the sample being examined.
Recently, digital imagers have been coupled to compound or stereo microscopes in order to digitize and manipulate magnified images of an object under examination. In the most widespread application, a digital camera or imager is attached to the microscope either at an eyepiece assembly, or at a dedicated port. The images captured by the imager are then typically fed into a computer and displayed on a monitor or stored for later usage. In addition, recent digital imagers have been attached to compound microscope assemblies without eyepieces for direct human observation.